Piezoelectric ceramic, method for making the same, piezoelectric element, liquid discharge head, and ultrasonic motor

Abstract

A piezoelectric ceramic that includes barium titanate and 0.04 mass % or more and 0.20 mass % or less manganese relative to barium titanate. The piezoelectric ceramic is composed of crystal grains. The crystal grains include crystal grains A having an equivalent circular diameter of 30 μm or more and 300 μm or less and crystal grains B having an equivalent circular diameter of 0.5 μm or more and 3 μm or less. The crystal grains A and the crystal grains B individually form aggregates and the aggregates of the crystal grains A and the aggregates of the crystal grains B form a sea-island structure.

What is claimed is: 
     
       1. A method for making a piezoelectric ceramic, comprising:
 sintering a mixture at least containing barium titanate particles 1 containing 0.05 mass % or more and 2.0 mass % or less manganese on a metal basis and barium titanate particles 2 containing less than 0.04 mass % manganese on a metal basis, 
 wherein the piezoelectric ceramic comprises:
 barium titanate; and 
 0.04 mass % or more and 0.20 mass % or less manganese relative to barium titanate, 
 wherein the piezoelectric ceramic is composed of crystal grains, 
 the crystal grains include crystal grains A having an equivalent circular diameter of 30 μm or more and 300 μm or less and crystal grains B having an equivalent circular diameter of 0.5 μm or more and 3 μm or less, and 
 the crystal grains A and the crystal grains B individually form aggregates and the aggregates of the crystal grains A and the aggregates of the crystal grains B form a sea-island structure. 
 
 
     
     
       2. The method according to  claim 1 , wherein the content of the barium titanate particles 1 in the mixture is 2 mass % or more and 90 mass % or less.